As is known in the art, the hermetic compressors are devices widely used in refrigeration systems in general, the components being responsible for providing the circulation of the refrigerant fluid through the tubing of the cooling systems. The suction and discharge connector pipes have the function of conducting the refrigerant gas through the compressor housing, connecting the inside thereof to the pipes of the refrigeration system. The connector tube of process has the function to be the pathway of oil and/or refrigerant fluid injection during installation of the compressor in the refrigeration system. It should be clarified that such connector pipes are typically made of copper due to the ease of connection by brazing with the pipes of the system.
It happens, however, that the proper operation of such equipment also depends on the perfect sealing conditions between these connector pipes and the compressor metal housing, being such connector pipes produced in copper and the compressor housing generally manufactured in steel, such welding process becomes significantly complicated.
The most known form of assembly provides the use of brazing additional materials which are arranged between the hole of the compressor housing and the connector tube as disclosed, for example, in document JP2010038087. Although this document involves the use of a connector pipe without needing prior conformation, such process presents however the disadvantage of needing the use of addition material for welding.
An alternative technique is presented in document CN101780602 (see FIGS. 2 and 3 attached) which provides the use of upper 200 and lower 201 electrodes disposed in order to involve the entire outer surface of connector pipes 110, these electrodes being responsible for the passage of a electrical current from 30,000 to 50,000 Amperes for about 30 to 80 milliseconds to heat the copper and make it pliable to, by applying a compressive force, weld the flange copper of the connector tube 110 on the surface of the housing 2 with which it is in contact. It happens, however, that such process requires the existence of a flange (111) in the body of the copper dowel—that is, the need of further steps in the process, making it more complex and more expensive compared to the solution proposed herein.
Another example of installation of connector pipe in hermetic compressors was disclosed in document PI0603392-0, in which connector pipes 110 previously conformed and also necessarily provided with flanges 111—which constitute the coupling means of the piece—are welded directly to housing 2 of compressor C by means of the application of electrical current through electrodes 200/201. The drawbacks of this process relate to the fact that it is required a prior conformation of flange 111 before the welding operation, requiring a complex operation additional to the production process, and it is more expensive when compared to the solution proposed herein.
Note that all processes of the current state of the art demand the introduction of the ends of connector pipe 110 inside the suction and discharge holes of compressor C. Therefore, it is noted that the current state of the art lacks a welding process which, besides being more efficient, simple and economical, also allows the welding between the parts is of the “top” type, thus eliminating the need of previous shaping of the copper pipes to the production of flanges for welding and eliminating the need to use addition material for brazing. The current technique also lacks a process that allows the shaping and welding of connector pipes to compressor casings to be made in a single step and, therefore, significantly more rapid and economical.